The present invention relates to a rack-type kinematic mechanism, in particular for vehicle lifts.
In the mechanical engineering field, various types of vehicle lifts are known, which are in use in mechanical engineering workshops and similar environments, in order to provide convenience access to the parts beneath the vehicle. Thus, lifts have been developed with columns which are on view, in which the rails, runways or arms to support the vehicle are translated along two or four uprights, which are secured vertically to the floor; recessed column-type lifts, which are similar to the previous type, but in which the columns are at least partially embedded below the floor; and finally lifts with scissors-type articulation, which are preferably also. recessed, in which the vertical movement of the rails or the like is provided by a scissors-type articulation disposed at the base.
Irrespective of their type, the lifts always contain cylinders., which are normally of the oleodynamic, i.e., hydraulic, type, and are designed to move the lift. In the known lifts, the kinematic mechanism is such as to require substantial cylinder dimensions, with consequent disadvantages in terms of dimensions when the lift is lowers, and of costs.
U.S. Pat. No. 4,495,828 discloses a rack-type kinematic mechanism comprising a first, fixed rack and a second rack which is mobile and supports a lifting unit. Two toothed wheels being connected by a chain are interposed between the racks. The toothed wheels are integral with movement means for the lift, such that-the lifting unit travels a path which is twice that of the movement means for the lift. In the initial position the two racks are arranged parallel to each other. In the expanded arrangement the toothed wheels are disposed at the opposite ends of the racks. The maximum stroke of the lifting unit corresponds to about the length of the mobile rack.
U.S. Pat. No. 1,486,797 discloses a lift for vehicles wherein one toothed wheel is interposed between a first, fixed rack and a second, mobile rack. The stroke of the mobile rack is limited to about the length of the mobile rack.
The object of the present invention is to provide a vehicle lift, which permits use of smaller dimensions, for the same ratio between. the maximum height of lifting and size when the lift is lowered.
This problem is solved in the vehicle lift by means of a rack-type kinematic mechanism that maximizes the lift""s elevation range and optimizes its size. Further advantageous characteristics of the said kinetic mechanism are indicated below.